Method and apparatus for winding conical cross-wound coils or bobbins with constant thread-feeding velocity

ABSTRACT

Method of winding conical cross-wound coils at constant thread feed velocity wherein compensation is provided by a storage device for the varying winding speeds from the larger to the smaller diameters of the coils which includes setting a thread storage device in zero position thereof, wherein no thread is being stored, after alternative occurrence of a coil change and a thread break; initially holding with an auxiliary thread guide a thread that is to be wound into a coil; advancing a thread guiding member in a direction from the larger toward the smaller diameter ends of the coil and, after releasing the thread from the auxiliary thread guide, taking over the thread with the thread guiding member.

The invention relates to a method and apparatus for winding conicalcross-wound coils or bobbins with constant thread-feeding velocity.

When a conical cross-wound bobbin is driven with constant peripheralvelocity in a textile machine, variations in the instantaneous windingspeed occur in the course of winding this coil, because the thread iswound at the narrow or wide end of the bobbin or in the middle of thebobbin, depending upon the position of the thread guiding member.

The varying winding velocity must be equalized or compensated for, whenthe thread is fed at constant velocity, as is the case, for example, inspinning frames.

For this purpose, it has been proposed heretofore to dispose a threadstorage device between the winding device and the threadfeedingmechanism. Such a thread storage device is formed, for example, of aspring- or weight-loaded compensating roller, which produces a threadloop of continuously changing length which meets the requirements of thewinding process.

In starting up such a winding apparatus, difficulties are encountered,because at the instant of starting, the length of the stored thread isundetermined. The stored thread will only purely accidentally have alength corresponding to the position of the thread guiding member. Inall other cases, the length of the stored thread is either too great ortoo small. Both are disadvantageous. When the stored length is toosmall, excessive thread tension occurs during start-up, which may resultin a thread break.

When the stored length is too great, there is either no thread tensionat all, or not enough of it. Disruptions due to uncontrolled threadmovements result especially therefrom. The thread can loop around thethread guide and consequently break.

It is accordingly an object of the invention to provide a method andapparatus for winding cross-wound coils or bobbins with constantthread-feeding velocity which avoids the foregoing disadvantages of theheretofore known methods and apparatus of this general type. Morespecifically, it is an object of the invention to provide such a methodand apparatus which will ensure that a winding device for conicalcross-wound bobbins will operate with substantially constant threadtension from the very first instant of start-up, so that disruptions dueto excessive or insufficient thread tension or due to no thread tensionat all, are avoided.

With the foregoing and other objects in view, there is provided inaccordance with the invention, a method of winding conical cross-woundcoils at constant thread feed velocity wherein compensation is providedby a storage device for the varying winding speeds from the larger tothe smaller diameters of the coils which includes setting a threadstorage device in zero position thereof, wherein no thread is beingstored, after alternative occurrence of a coil change and a threadbreak; initially holding with an auxiliary thread guide a thread that isto be wound into a coil; and advancing a thread guiding member in adirection from the larger toward the smaller diameter ends of the coiland, after releasing the thread from the auxiliary thread guide, takingover the thread with the thread guiding member.

The zero position or neutral setting of the thread storage device isdefined as that position in which the available stored thread contenthas just become zero so that upon start-up the storing process beginsanew.

In accordance with another feature of the invention, the method includesrotating the coil and wherein the thread is held by the auxiliary threadguide at a location along the length of the coil at which the peripheralvelocity of the coil is substantially equal to the velocity of feed ofthe thread. This ensures that the thread tension remains constant evenwhen the thread is not wound with crossed thread layers.

In accordance with the device of the invention for carrying out theforegoing method, there is provided an auxiliary thread guide located ateach winding station of a textile machine, the auxiliary thread guidebeing adjustable at start-up of the winding method to an engageableposition wherein a thread is guided thereby for winding on a coil and toa disengageable position wherein the thread is transferred by theauxiliary thread guide to a thread guide member, the auxiliary threadguide in the engageable position thereof being disposed so as to directthe thread to a location along the length of the coil at which theperipheral velocity of the coil is equal substantially to the velocityof feed of the thread.

In accordance with another feature of the device of the invention, theauxiliary thread guide is formed of a bracket having a saddle-likedepression therein.

To allow a transfer of the thread to the thread guiding member only whenthe latter is travelling in the direction toward the smaller diameterend of the coil, in accordance with a further feature of the invention,the thread guide member is formed with a hook-shaped thread catchcontour open in direction facing toward the smaller diameter end of thecoil.

In order to start a winding station up, the position of the threadguiding member and of the thread storage device must be coordinated.Therefore, in accordance with an additional feature of the invention,the thread storage device is cooperatively connected with the auxiliarythread guide, the thread storage device being lockable in the zeroposition thereof.

It is further advantageous, in this regard, to couple the locking meanswith the disengagement means of the auxiliary thread guide. Inaccordance with another feature of the invention, consequently,mechanism is provided for adjusting the auxiliary thread guide to thedisengageable position thereof, the thread storage device being lockablein zero position thereof by means coupled to the mechanism. Locking ofthe thread storage device can thus be neutralized and the auxiliarythread guide can be disengaged simultaneously by having it lock with thedrive mechanism of the thread guiding member, when the thread guidingmember is travelling in direction toward the smaller diameter end of thecoil.

Further advantages derived from the invention are, in particular, thatstart-up of the winding device occurs with substantially constant threadtension and thread breaks due to excessive thread tension oruncontrolled thread movements are avoided.

Other features which are considered as characteristic for the inventionare set forth in the appended claims.

Although the invention is illustrated and described herein as method andapparatus for winding conical cross-wound coils or bobbins with constantthread-feeding velocity, it is nevertheless not intended to be limitedto the details shown, since various modifications may be made thereinwithout departing from the spirit of the invention and within the scopeand range of equivalents of the claims.

The invention, however, together with additional objects and advantagesthereof will be best understood from the following description of thesingle FIGURE of the drawing which is a perspective view of apparatusfor winding conical cross-wound bobbins with constant thread-feedingvelocity according to the invention.

Referring now to the drawing, there is shown therein a winding stationof a textile machine, having a supporting beam 11 with a base plate 12fastened thereto. A winding roller 14 is secured on a shaft 13, whichextends from winding station to winding station, the winding roller 14having in the middle thereof, a zone 15 with a high coefficient offriction which ensures that a conical cross-wound coil 16, which rollsaround on this zone 15 of the winding roller 14, will always be drivenin the middle of the roller 14 and, accordingly, in the middle of thebobbin.

In special cases, the zone 15 having a high coefficient of friction canalso be omitted. Because the drive zone is then no longer defined,changes in the slippage between the winding roller 14 and the bobbin 16must be expected, which has an adverse effect on the desired uniformthread tension and also on the stress on the thread.

A centrally controlled thread-guiding member 18 is movable back andforth in the directions indicated by the double-headed arrow by means ofa control rod 17, which extends from winding station to winding station.The thread-guiding member 18 has a hook-shaped thread-catching contour19 which is open in direction toward the small diameter end of thebobbin and serves for receiving and simultaneously guiding the thread 20that is to be wound.

The thread 20 is fed with preferably constant feeding velocitycontinuously upward from below, as shown in the FIGURE, out of anon-illustrated feeding mechanism.

In a thread storage device 21, the thread 20 forms a loop 22 in that itis suitably deflected by a deflecting member 23 attached to the baseplate 12, a movable deflecting member 24 secured to the end of a storagedevice lever 26 and a third deflecting member 25 which is also fastenedto the base plate 12. The deflecting members 23, 24 and 25 areconstructed as easily turning rollers with machined thread-guidinggrooves.

The storage device lever 26, pivotable about a pin 27, has a zeroposition stop which is formed of a stop latch 29 pivotable about a pin28, and a stop pin 30 secured to the stop latch 29, a stop arm 31 of thestorage device lever 26 striking against the stop pin 30.

Since the stop latch 29 is held in position only through a coiledtension spring 32 so that it is drawn with a projection 33 thereofagainst a pin 34 secured to the base plate 12, the storage device lever26 can be moved manually out of the zero position or neutral settingthereof and further to the left-hand side as viewed in the figure, afterthe spring force of the coiled tension spring 32 has been overcome, afeature that could be useful, for example, for inserting the thread 20after a thread break.

The stop arm 31 of the storage device lever 26 is connected to an end ofa tension spring 35, the other end of which is secured to the base plate12. Under the biasing action of the spring 35, the storage device lever26 is capable of drawing a thread loop of required length toward theright-hand side, as viewed in the figure. The spring force, in thatcase, acts advantageously on a lever arm that becomes increasinglylonger with growing angular displacement of the storage device lever 26about the pivot 27.

In the drawing, the thread storage device 21 and the thread guidingmember 18 are shown in zero position or neutral setting thereof. In thisposition, a thread loop has already been formed, there is no storedsupply of thread.

An engageable and disengageable auxiliary thread guide 36, formed of awire bracket has an end 37 by which it is articulatingly connected to acontrol lever 38, which is pivotable about a pivot shaft 39. The controllever 38 has a handle 40, by means of which the auxiliary thread guide36 can be engaged and disengaged. The drawing shows, in solid lines, theauxiliary thread guide 36 in disengaged position. In this disengagedposition, the control lever 38 and the auxiliary thread guide 36,therewith, are locked by a locking latch 41, which is articulatinglysecured to the ground plate 12 and has an angularly projecting end 43which engages with the upper edge of the lever 38, as viewed in thefigure, under the biasing action of a coil spring 42.

When placing the auxiliary thread guide 36 in engaged position as shownin phantom at 44, the locking latch 41 is drawn to the right-hand sideof the figure and the handle 40 is raised until the control lever 38 hasreached the position 45, shown in phantom. Because the angularlyprojecting end 43 of the locking latch 41, in the engaged position ofthe auxiliary thread guide 36, resiliently engages the vertical part ofthe control lever 38, as shown in the figure, the auxiliary thread guide36 also is locked in the engaged position thereof.

For raising and lowering the auxiliary thread guide 36, the latter isprovided with a parallel guidance system which is formed of a lever 46pivotable about the pin 28, and a tie rod 47 articulatingly linked tothe lever 46 and the control lever 38. The bracket end 53 of theauxiliary thread guide 36 is articulatingly connected to the end of thelever 46.

In the engaged position of the auxiliary thread guide 36, shown inphantom in the drawing, the movement of the storage device lever 26 isblocked. This is accomplished in the following manner. The control lever38 carries a locking latch 49 which is pivotable about a pin 48 andengages a stop pin 51 under the biasing action of a coil torsion spring50.

The moment the control lever 38 has reached the position 45 thereofshown in phantom, the locking latch 49 engages behind a stop pin 52attached to the rear side of the storage device lever 26 and thusprevents the storage device lever 26 from swinging to the right-handside of the figure. This locking of the storage device lever 26 can beneutralized manually by swinging the locking latch 49 downwardly againstthe biasing force of the coiled torsion spring 50.

When the auxiliary thread guide 36 is placed in the engaged position,the thread 20 slides out of the reciprocating thread guide member 18 andis directed toward the middle of the bobbin by the auxiliary threadguide 36, which is formed with a saddle-like depressed portion withinthe region of the thread guide 18. After this has occurred, the threadis wound in the middle of the bobbin for as long as the auxiliary threadguide 36 is engaged. Because of the coordination of the feed of thethread and the speed of rotation of the bobbin, the thread feed velocityis equal to the winding velocity. No thread storage takes place. Thethread tension is substantially constant.

When the auxiliary thread guide 36 is disengaged, the thread isre-transferred to the thread guiding member 18. Because of the threadcatching contour 19, the transfer can occur only in the zero position orneutral setting of the thread guiding member 18. At the instant ofthread transfer, the previously locked storage device lever 26 isunlocked, so that the winding process per se with crossed thread layersbegins only then.

There is claimed:
 1. Method of winding conical cross-wound coils atconstant thread feed velocity wherein compensation is provided by astorage device for the varying winding speeds from the larger to thesmaller diameters of the coils which comprises setting a thread storagedevice in zero position thereof, wherein no thread is being stored,after alternative occurrence of a coil change and a thread break;initially holding with an auxiliary thread guide a thread that is to bewound into a coil; advancing a thread guiding member in a direction fromthe larger toward the smaller diameter ends of the coil and, afterreleasing the thread from the auxiliary thread guide, taking over thethread with the thread guiding member.
 2. Method according to claim 1which comprises rotating the coil and wherein the thread is held by theauxiliary thread guide at a location along the length of the coil atwhich the peripheral velocity of the coil is substantially equal to thevelocity of feed of the thread.
 3. Device for carrying out the method ofwinding conical crosswound coils at constant thread feed velocitycomprising an auxiliary thread guide located at each winding station ofa textile machine, said auxiliary thread guide being adjustable atstart-up of the winding method to an engageable position wherein athread is guided thereby for winding on a coil and to a disengageableposition wherein the thread is transferred by said auxiliary threadguide to a thread guide member, said auxiliary thread guide in saidengageable position thereof being disposed so as to direct the thread toa location along the length of the coil at which the peripheral velocityof the coil is equal substantially to the velocity of feed of thethread.
 4. Device according to claim 3 wherein said auxiliary threadguide is formed of a bracket having a saddle-like depression therein. 5.Device according to claim 3 wherein said thread guide member is formedwith a hook-shaped thread catch contour open in direction facing towardthe smaller diameter end of the coil.
 6. Device according to claim 3including a thread storage device cooperatively connected with saidauxiliary thread guide, said thread storage device being lockable inzero position thereof.
 7. Device according to claim 6 includingmechanism for adjusting said auxiliary thread guide to saiddisengageable position, said thread storage device being lockable inzero position thereof by means coupled to said mechanism.